


Puzzling Development

by heartsdesire456



Category: Shadowhunters (TV)
Genre: Bickering, Bisexual Jace Wayland, Comedy, Coming Out, Established Relationship, Friends With Benefits, M/M, Sexual Humor
Language: English
Status: Completed
Published: 2017-06-06
Updated: 2017-06-06
Packaged: 2018-11-09 18:17:28
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,646
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11110173
Author URL: https://archiveofourown.org/users/heartsdesire456/pseuds/heartsdesire456
Summary: In his long life, Magnus had known all manner of people and seen all sorts of odd matches. There were so many couples he absolutelydid notunderstand for the life of him. There were mysteries that made no sense when it came to matters of the heart (or the flesh, for that matter), and he had known just about every type of possible situation imaginable in his day.And then there was Simon and Jace.





	Puzzling Development

**Author's Note:**

> This is ridiculous and only exists because my friend and I joked about how Jace would be super lazy during sex. Don't take this one too seriously, my friends.

In his long life, Magnus had known all manner of people and seen all sorts of odd matches. There were so many couples he absolutely _did not_ understand for the life of him. There were mysteries that made no sense when it came to matters of the heart (or the flesh, for that matter), and he had known just about every type of possible situation imaginable in his day.

And then there was Simon and Jace.

He had absolutely no idea what the hell happened to bring _that_ on, except that after Simon drank from Jace and became a daylighter, it didn’t take long before Simon and Clary decided to go back to being friends and instead of Clary get with Jace, who had revealed they were not, in fact, siblings, Magnus came home from a lovely date with Alexander to have them both assaulted by the sounds of what could only be rather athletic passion going on in Jace’s guest room.

Plans to get busy with Alec were suitably ruined by the rather vocal pair in the other bedroom, and instead they resigned themselves to sitting out on the terrace, free of the horrific sounds, and cuddling in the evening chill. 

It wasn’t a total loss, just not the ending to the evening Magnus planned for.

What they _did not_ expect when they went back inside when they began to fall asleep while talking, their plans to go to sleep were also temporarily delayed by the sight of _Simon_ walking around the kitchen getting coffee. “Um, not that you’re not welcome if you need help, Sherwin, but why are you in my house at two in the morning, and why are you getting coffee? You drink blood, remember?”

Simon flushed. “I- uh- I’m…”

“Simon, I said I wanted coffee, did you go to Starbucks or somethiiiiiii…. Oh, hey Magnus.” It only took one look at Jace sans shirt and Simon’s suspiciously extra-puffy curls to put two and two together and get-

“What the fuck?!” Alec looked between the two of them, looking somewhere between confused, horrified, and angry. 

Simon laughed awkwardly. “Magnus, Alec, hi! I’m… totally here for the reasons you think,” he trailed off, scratching at his neck as he shoved the mug of coffee out at Jace. “Take this before I drown myself in it.”

Jace rolled his eyes but took the mug of coffee. “It’s simple: we’re both single, horny, and kinda slutty,” he said before sipping his coffee with a shrug.

“You’re straight,” Alec said flatly and Jace hummed.

“Yeah, well, I don’t have to like him to like sex with him,” he said as if that made any sense at all. 

“You know, there’s a little more to it than that,” Magnus drawled, looking between them. “I’m quite intimately aware of the differences in sex with men and sex with women, if you don’t remember.”

Simon hummed. “I did wonder about that,” he said, looking at Jace. “If you’re straight…” He trailed off, wiggling his eyebrows as if trying to ask a question without saying it in front of Magnus and Alec.

Jace smirked. “What? You act like strap-on’s don’t exist,” he said with laughter in his voice, as if he found the entire ordeal amusing.

For the rest of them, however, it was clearly not. Magnus’s jaw dropped, Simon flushed, and Alec closed his eyes and took a slow breath through his nose. “Yep. That’s it. I’ve got to go kill myself now.” He put a hand on Magnus’s shoulder. “Magnus, I love you, but I need you to make my suicide look like a hero’s death.”

Simon frowned. “Didn’t you used to be into Jace anyways? Can’t be that traumatizing-“

“I never thought about it in detail or else I would’ve figured out sooner I was super not into Jace actually,” Alec spluttered. “Ew, this is worse than when I found Isabelle’s porn collection!” he complained, holding up a hand as he left the room. “I’m going to sleep, never wake me up, just let me rot.”

Jace grimaced. “Izzy’s porn collection. I’ll never forget that,” he said, shuddering. “Oh well, when Alec’s done with his dramatics, tell him I’ll see him tomorrow,” Jace said to Magnus, then turned to head back down the hall. “Simon!”

Simon awkwardly saluted Magnus and rushed after Jace without another word.

After that incident, quite a few times Magnus came home to Jace and Simon having sex there, even though now Jace was welcome back at the Institute and it was Simon living in his spare room. 

After enough times, he put a silencing spell on the guest room so he didn’t have to hear the really, inordinately loud sex. He was pretty sure he and Alec weren’t that loud in bed and neither he nor Alec were silent during sex in the least. There was a difference, however, in ‘you would hear the moans if you were quiet outside the bedroom door’ and Jace sounding like he was auditioning for a very alarming porno. 

One day, he had invited the girls over for brunch on a morning Alec had stayed the night, and when Jace sauntered out of Simon’s room to join them, about halfway through the meal he casually said, “I think I’m bisexual,” when Isabelle asked where he had been spending all his free time lately. 

Alec rolled his eyes. “Wow, what ever gave you that idea.”

Isabelle raised an eyebrow. “We’re missing something, aren’t we?” she asked, gesturing between here and Clary.

Clary, however, snorted. “I may have forgot to mention to you, but Simon and Jace have been sleeping together,” she said, and Isabelle gave Jace a flat look.

“You’re sleeping with a guy and just now think you might be bisexual?” she asked incredulously. 

Jace shrugged. “I’ve just never really thought about it. Most of the people I sleep with are women.”

“Most,” Magnus said in surprise. “You mean you’ve slept with non-lady people other than Simon and still only just, after three weeks of turning my house into a porn studio, think you’re bisexual.”

“Well it’s not like I’d say no to a blowjob unless I was sure it was a woman,” Jace said as if stating the obvious. “Those fairies are hard to tell sometimes. They’re fairly androgynous, so you can’t be sure.”

Magnus opened his mouth and then closed it again, but then decided he couldn’t not ask. “Um, don’t you find out once you return the favor?”

Isabelle snorted. “Damn, Magnus, no wonder you’re so popular if you just assume reciprocation always happens.”

Alec made a disgusted face. “First, I would love to stop having this conversation, and second, how the hell do you get laid so much if you apparently have a pattern of leaving your date hanging?” Alec asked, looking like he so very much didn’t want to know but couldn’t stop himself asking.

Jace grinned. “Dude, Alec, you’re gay and have eyes.” He gestured to his face. “You have to ask how I get laid? Really?”

“You’re a six at best,” Magnus said honestly and Jace rolled his eyes.

“Oh please.”

Isabelle hummed. “Yeah, I’m biased _against_ finding my brothers sexually attractive, cause ew, and even I’d give Jace a solid eight,” she said. “Alec’s probably an eight, too, but that might just be because we look alike and I know I’m gorgeous.”

Magnus gaped. “There is no world in which Alec is an eight if Jace is an eight,” he said bluntly.

Alec blushed. “Magnus, I know you love me, but let’s be real, Jace is definitely the hot one,” he said sheepishly. 

Magnus turned to Alec and caught his eyes. “Alexander, I’ve slept with seventeen _thousand_ people, do you know how many of them caught my eye from across a crowded night club and made my _jaw drop_ ,” Magnus said frankly, looking at Alec. “Darling, you are easily one of the top ten most beautiful people I’ve laid eyes upon in my five hundred years on this earth, top three among people I’ve been with.” Alec ducked his head with a sheepish grin and both Clary and Isabelle ‘awww’ed at him. “I don’t even find Jace remotely attractive,” he finished, then glanced over at Jace. “No offense, you’re a great person and a brave Shadowhunter. And I’m sure your vampire thinks you’re handsome. I just have higher standards than most.”

Alec stuttered when he tried to speak, his eyes down at his lap. “That- Magnus- I-“ He blushed and put a hand over his eyes. “You’re ridiculous,” he said, though it was obvious he was smiling.

“Why’s Magnus ridiculous?” Magnus looked up as Simon walked in, wearing what was clearly Jace’s clothes, and sat down beside Clary, looking around the table. 

Magnus snapped his fingers and a mug of blood landed in front of Simon. “Because I think Alec’s one of the most gorgeous men I’ve ever seen and Jace isn’t even all that hot.”

Simon shrugged dismissively, sipping his blood, seeming to decide not to comment on that.

Jace just shrugged. “Fair enough, you’re not all that special for my tastes either,” he said and Magnus rolled his eyes. “Also, seventeen thousand sex partners in five hundred years? Damn.”

Alec gave him a warning look. “There’s nothing wrong with Magnus’s past, Jace.”

“Oh no, I was thinking that’s kinda low, honestly,” he said, chewing on a bite of toast. Magnus raised an eyebrow and Jace looked up at the ceiling, clearly thinking. “Simon, what’s the math on that?” he asked.

Simon hummed. “That’s like two or three a month on average going one at a time.”

Jace hummed. “And you seem like the ‘orgy’ kinda guy, so that would mean even less than that, assuming you count the individual participants. Wow, yeah, dude, that’s way lower than my number would be. I’ve only been having sex for seven years and the only reason I’m not over a hundred is because of injuries and work getting in the way of going out.”

Alec grimaced. “Jesus, _over a hundred_?”

Isabelle raised an eyebrow. “Damn, I really thought I’d have the highest number in this family, what the hell, Jace?”

Jace shrugged. “I mean, in the couple of weeks I was living with Magnus, I slept with like eight girls, since I didn’t have anything better to do.”

“Ew,” Clary said, rolling her eyes. “And I thought Simon got laid a lot.”

Magnus looked at Simon in surprise, as did everybody else at the table. Simon frowned. “What? It’s not like _Jace_ numbers,” he defended.

Alec didn’t miss a beat. “I’m more surprised you ever found someone blind enough to want to sleep with you.”

Magnus tutted. “Now, now, Simon’s a cutie in that ‘nerd hot’ kinda way,” he mused.

Isabelle nodded. “Definitely nerd hot, but I wasn’t expecting to hear he gets around,” she said, winking at Clary. “What’re we talking?”

“I don’t know the number or anything,” Clary stuttered. “I just- I know it’s enough that his mom is chill with him bringing girls home.”

“Even if I’m nerdy, I was in a band,” Simon said with a shrug. “I mean, I’m no Magnus, but nine people is a lot when I only started having sex like a year and a half ago.” He frowned. “Why are we talking about our sex numbers again?”

“Cause Magnus has had way less sex than I would if I was his age,” Jace reminded him.

Magnus chuckled, shaking his head. “Believe it or not, just because I’ve lived a life of indulgence in worldly pleasures, that doesn’t mean I’m a sex fiend. I’m better suited for monogamy, actually, I just don’t get that very often.” He smiled sadly down at his plate. “Shocking, I know, but not that many people want to have a long-term relationship with a Warlock.”

Alec slid his hand into Magnus’s under the table and Magnus squeezed it, glancing at Alec’s warm look. They had talked about Magnus’s past in more detail since they had confessed their love. Alec knew all about Magnus’s very few and far between actual relationships. He knew that once, Magnus had been with one woman for seventeen years before she left him because she wanted to get married and have a family, something she couldn’t do with him, and how it had been the greatest heartbreak of his long life, mostly because he understood why and never could resent her for it. He and Alec hadn’t really talked about the future much, since things were still so new, but Alec knew that what Magnus longed for was a long-term, monogamous relationship, something he hadn’t had in more than half a century.

Jace ruined his and Alec’s private little moment of affection by grumbling. “If I was immortal, I’d probably try and sleep with as many people as I could to set a record or something,” he mused. “And since I’ve decided I’m bisexual, that doubles the number of people I could do,” he said, sounding almost excited.

“Oh, you’re bisexual finally? I missed that,” Simon grunted, sounding annoyed. “It only took several weeks of sleeping with me to do it.”

Jace grinned. “Hey, you helped at least. I just didn’t really think about it before.” He sipped his juice. “Speaking of, you done?” he asked, nodding at the blood Simon was drinking.

Simon rolled his eyes. “I’m going to finish my blood and talk to my friends, thanks.”

Jace raised an eyebrow. “You’re picking talking over sex with me?” he asked flatly.

“Well at least a conversation isn’t one-sided,” Simon muttered, and everybody stopped moving at once. Magnus glanced at Simon and then saw everybody else was doing the same. 

Jace blinked. “Excuse me? Are you actually complaining about _sex_ with _me_?”

Simon raised an eyebrow. “You act like it’s a privilege to do all the work just to have you complain the whole time.”

“Maybe I wouldn’t complain if you were better in bed,” Jace countered incredulously. 

Simon set his mug down. “Yeah, well, there’s only so many times you can really give your all to having sex with what amounts to a _log_. If I wanted to fuck a mannequin, I’d buy a sex doll,” he said and Magnus’s jaw dropped as Isabelle gasped and then laughed audibly. 

Jace laughed humorlessly. “Do you see this?” he asked, gesturing to this. “And all of this,” he added, gesturing to his body. “Do you know how many people go out of their way to get me naked?”

“Probably there’s so many because people get sick of how lazy you are in bed,” Simon said simply. “For once, you could ride me.”

Jace tossed his bangs out of his face. “Yeah well, for once you could actually last long enough to make me finish first.”

“Well it would be easier if you’d give foreplay a shot-“

“It would be easier if you could actually find my prostate-“

“I’d have an easier time if you didn’t complain every time I suggested we try a new position-“

“It’s sex, not yoga-“

“Oh my God, you are the most stubborn man I’ve ever met-“

“You’re not nearly hot enough to be picky, a big dick and cute smile isn’t nearly enough to turn _me_ down-“

Simon threw his hands up. “Holy shit, fine!” He downed the rest of his blood and then stood up. “Jesus Christ, if fucking you will shut you up, let’s go,” he said, storming out of the room. Jace rolled his eyes but stood up and followed him.

Magnus looked around the table and saw confused or appalled looks on faces. “Don’t worry, that room has a silencing spell on it. I learned the hard way that Jace thinks he’s a cheap porn star.”

Isabelle grimaced. “Oh boy,” she said, and Alec nodded with a grave look on his face.

“Exactly.”

**Author's Note:**

> I might write a sequel to this if the fancy strikes me, showing Jace and Simon's side of the story, but don't hold your breath.


End file.
